(a) Field of the Invention
The present invention relates generally to V/STOL aircraft, and in particular to utilizing the thrust of V/STOL aircraft developed by an engine driven fan for providing thrust modulation and thrust vectoring throughout various flight modes including hover, vertical ascent, descent and forward motion.
(b) Prior Art
We are familiar with one approach to V/STOL operation which utilizes a tilt nacelle configuration often with an additional fan in the nose or tail to provide pitch and yaw control. This approach has resulted in extremely complex and rugged rotation mechanisms imposing a serious weight penalty on the aircraft.
In another approach, the propulsion system is mounted in a fixed position and various means are provided for deflecting the outflow from the propulsion system to achieve the desired thrust vectoring. Such a fixed propulsion system usually requires an additional fan for pitch and yaw control. Also, such outflow deflecting systems have usually resulted in high thrust losses in one or both modes of operation and have additionally failed to provide the required smooth operation during transition from one flight mode to another. In addition, neither provides any significant augmentation of the aerodynamic lift for the aircraft transitioning from vertical flight to forward flight or vice-versa. Furthermore, with such present-day systems, rapid and efficient pitch, roll and yaw control of the aircraft in the low speed (including hover) and STOL flight modes have not been obtained and those systems have less than ideal short rolling takeoff capability when overloaded.